Transverter RX switch

dlwarnberg

Here is my setup, I have a flex 6500, a 70 cm and a 2 meter elecraft transverters, M2 sequencers, an M2 LEO pack with a Yaesu G-450A rotator...

Here is the issue, I discovered the 70cm side was def, I could transmit fine, worked several of the XW-2x sat's wihout issue, but I still could not hear anything from my local repeaters on the 70cm side.  My HT could pick them up fine.  After a day of troubleshooting I discovered the switch box I am using to switch RX between 2 meters and 70cm is the issue.  I take a direct cable from the RX side of the radio to the RX on the transverter and several things happen, noise level drops like a rock, I can hear EVERYTHING... so my switch is BAD.

Question, for those of that have the same setup what switch are you using?  I have a generic "Data Transfer Switch" I ordered from amazon and am having a hard time finding a good switch.

Suggestions?

Thanks

David

George KF2T

Any good coax switch rated for the frequencies in question should work. I use a Daiwa 4-position coax switch for exactly the same receiver configuration. Works perfectly.

dlwarnberg

George, so you are using adapters between I would guess.. was hoping to avoid that but from what I'm seeing it's night and day difference with a direct hookup..

Thanks

dlwarnberg

Guess this is why you don't buy cheap switches...

George KF2T

You can make cables with the matching connectors, but at 28 MHz a BNC to UHF adapter is no biggie. Just use good cable to prevent undesirable IF ingress.

WX7Y

you could also try building a power divider, being this is all on RX it is not very difficult. 

all you need is a small metal box (Like a Altoid tin) 3 BNC chassis jacks (or what ever you need) and  resisters, the down fall is it will have 3db of loss which you may already be making up with pre-amps. 
See the schematic below

73's 
Bret
WX7Y

dlwarnberg

Thank you.. I'm all about building stuff...  and yes I am using preamps.

Thanks again

George KF2T

Tricky thing to have both transverters on the same IF at the same time. Could get messy.

Simon Lewis

David

your problem lies in that this is not suitable for switching RF around

I am not surprised it goes deaf ... the switch is a DC switch and certainly not designed to switch RF

for a manual switch you need something that is designed to switch RF that will be low loss and also present good isolation

https://www.dxengineering.com/search/part-type/antenna-switches-manual


Something like this

https://www.dxengineering.com/parts/alf-delta-2b-n

this is rated to beyond 432 MHz

be wary of cheap SO239 switches designed for HF - your liable to find the DC switch again in a different box!


You could also find yourself an SMA relay and build that into the box

But use proper screened cables not single core DC wiring!

You can build something too if you like kits

Something like this

http://tapr.org/kits_tass.html

just buy a cheap SMA relay and some BNCs-SMA leads off ebay and reuse the box

but skip the DC switches - the loss through that will be horrific!

Cheers

Simon ZL4PLM 

dlwarnberg

Thanks Simon